While the Democrats may not come away completely empty-handed, it appeared unlikely by the end of the intense two-hour argument that a majority of the court would overturn the 2003 redistricting plan, or any other plan, for that matter, as an unconstitutional partisan gerrymander.
The new districts were drawn under a plan that was engineered by Representative Tom DeLay of Texas, then the House majority leader, after Republicans gained control of both houses of the Texas Legislature. And they are not necessarily invulnerable. Several justices, including, most significantly, Justice Anthony M. Kennedy, who may be in a position to cast the deciding vote, expressed concern with aspects of how particular districts were dismantled and reconfigured.
As a result, it appeared possible that the court would find a violation of the Voting Rights Act or the Constitution's equal protection guarantee in the way the new lines were drawn in South Texas. The legislators removed 100,000 Mexican-American residents of Laredo from a district in which the Republican incumbent, Representative Henry Bonilla, had become more vulnerable with each passing election, while creating a new Latino-majority district in a narrow strip running 300 miles from Austin to the Mexican border.
Justice Kennedy, addressing R. Ted Cruz, the Texas solicitor general, called the new district "a serious Shaw violation," a reference to the court's landmark 1993 case, Shaw v. Reno, that opened such oddly shaped districts to challenge as racial gerrymanders. The removal of the Mexican-Americans from the Laredo district, leaving the Latino population a bare statistical majority there but not numerous enough to control electoral outcomes, was an "affront and an insult," Justice Kennedy said.
Texas is holding its primary election Tuesday, and the Supreme Court's disapproval of even one of the 32 Congressional districts, in a decision that is not likely to come until early summer, would set off a new political scramble. But the prospect that the justices would declare the entire 2003 enterprise to be invalid appeared slight.
After Paul M. Smith, arguing for the Democrats, declared that the "whole map" was unconstitutional as "wholly lacking in any legitimate public purpose," Justice David H. Souter seemed to be having second thoughts about whether a political gerrymander could go too far.
"The difficulty I have," Justice Souter said to Mr. Smith, "is that it is impossible, and let's even assume it's undesirable, to take partisanship out of the political process." Mr. Smith's position, Justice Souter said, might "imply the illegitimacy of any redistricting."
Mr. Cruz, the Texas state lawyer, appeared to make some headway in defending the 2003 redistricting as an appropriate effort to counter "one of the most profoundly anti-majoritarian maps in the country," as he described the district lines drawn by the state's Democratic-controlled Legislature after the 1990 census.
Texas picked up two Congressional seats in the 2000 census. Republicans had gained control of the State Senate by then. The divided Legislature deadlocked over redistricting and left the job to a federal court, which based the 2001 plan largely on the one from a decade earlier. By drawing a new plan in 2003, after winning the State House, the Republicans were simply taking back a legislative prerogative from the court, Mr. Cruz said.
"The framers chose political checks for the problem of partisan gerrymandering," he said.
A special three-judge federal district court in Austin upheld the redistricting last year. Of seven appeals generated by that ruling, the Supreme Court agreed to hear four, consolidating them for two hours of argument; the lead case is League of United Latin American Voters v. Perry, No. 05-204. Nina Perales of the Mexican American Legal Defense and Educational Fund, arguing on behalf of Latino and black voters, made the South Texas redistricting the focus of her argument.
Texas violated the Constitution by "the excessive use of race," Ms. Perales said, particularly "to craft a razor-thin 50.9 percent Latino majority" in Mr. Bonilla's 23rd Congressional District. She said the Legislature chose to retain the narrow majority, down from 63 percent, to protect Mr. Bonilla and "give the false impression of Latino support."
Her argument brought the court into the heart of one of the most complex issues of voting rights law, the relationship between race and partisanship in political environments where race often serves as a rough proxy for party affiliation.
While the state argued, and the district court agreed, that the 100,000 Mexican-Americans were shifted out of the district because they were Democrats, Ms. Perales told the justices: "We contend that the state removed the Latino voters because they were Latino." Leaving just enough Mexican-Americans to create the "impression" of a Latino-majority district was "cynical," she said.
"What constitutional relevance does that have?" Chief Justice John G. Roberts Jr. asked Ms. Perales, adding: "What's the difference between 'being one' and 'looking like one?' "
The chief justice continued: "You're asking us to draw a very fine line. What's the magic number? What's the number that changes it from political nuance to a Hispanic-opportunity district? Would it have been better in your view if they had excluded more Hispanics so it didn't 'look like' a majority?"
Ms. Perales replied that each district must be evaluated for its own circumstances but that it was impermissible to "zigzag through neighborhoods and streets" in an "egregious use of race for its own sake." To uphold this district, she said, would "give states free rein to use race to manipulate outcomes."
Justice Antonin Scalia replied, "Of course you want to use race to manipulate outcomes, just sometimes."
Justice Scalia made his views clear throughout the argument. To Mr. Smith, he said at one point: "Legislatures redraw maps all the time for political reasons. To say it's something horrible is ridiculous."
Further, Justice Scalia said, even if there was a problem with middecade redistricting as a general rule, any such rule should not apply when a first redistricting after a new census had been done by a court rather than a legislature. "Surely that's a good reason" for the legislature to redistrict when it chose to, he said.
The plaintiffs are also challenging the Legislature's dismantling of a Dallas-Fort Worth district that had been represented for 13 terms by a Democrat, Martin Frost. While the district had been only about one-quarter black, black voters, through their high participation in the Democratic primary and their consistent support of Mr. Frost, had been able to keep him in office while most of the district's whites voted Republican. The district court held that, lacking a majority in the district, black voters could not bring a challenge to the district's dismantling under the Voting Rights Act.
This was erroneous, Mr. Smith argued, because the test under Section 2 of the Voting Rights Act was whether a minority group could effectively elect a candidate of its choice.
This argument gained little traction. "I don't see the limits of your principle," Justice Kennedy said. And Justice Stephen G. Breyer objected that because there were "many, many districts where African-American voters have influence on the Democratic Party," such an interpretation would greatly expand the reach of the Voting Rights Act.
Mr. Smith tried to be reassuring, saying his test would apply only when minority voters actually could control, rather than simply influence, electoral outcomes. "We're not just asking for the Voting Rights Act to become the Pro-Democrat Act," he said.
The Bush administration entered the case to defend the lower court's interpretation of the Voting Rights Act. Gregory G. Garre, a deputy solicitor general, argued that black voters did not, in fact, control the outcome in the old district.